Room temperature photolysis of the bis(azide)cobaltate(II) complex [Na(THF)(x)][((ket)guan)Co(N-3)(2)] ((ket)guan = [(tBu(2)CN)C-(NDipp)(2)](-), Dipp = 2,6-diisopropylphenyl) (3a) in THE cleanly forms the binuclear cobalt nitride Na(THF)(4){[((ket)guan)Co(N-3)](2) (mu-N)} (1). Compound 1 represents the first example of an isolable, bimetallic cobalt nitride complex, and it has been fully characterized by spectroscopic, magnetic, and computational analyses. Density functional theory supports a Co-III=N=Co-III canonical form with significant Jr-bonding between the cobalt centers and the nitride atom. Unlike other group 9 bridging nitride complexes, no radical character is detected at the bridging N atom of 1. Indeed, 1 is unreactive toward weak C-H donors and even cocrystallizes with a molecule of cyclohexadiene (CHD) in its crystallographic unit cell to give 1 center dot CHD as a room temperature stable product. Notably, addition of pyridine to 1 or photolyzed solutions of [((ket)guan)Co(N-3)(py)](2) (4a) leads to destabilization via activation of the nitride unit, resulting in the mixed-valent Co(II)/Co(III) bridged imido species [((ket)guan)Co(py)][((ket)guan)Co](mu-NH)(mu-N-3) (5) formed from intermolecular hydrogen atom abstraction (HAA) of strong C-H bonds (BDE similar to 100 kcal/mol). Kinetic rate analysis of the formation of 5 in the presence of C6H12 or C6D12 gives a KIE = 2.5 +/- 0.1, supportive of a HAA formation pathway. The reactivity of our system was further probed by photolyzing benzene/pyridine solutions of 4a under H-2 and D-2 atmospheres (150 psi), which leads to the exclusive formation of the bis(imido) complexes [(( ket)guan)Co(mu-NH)](2) (6) and [((ket)guan)Co(mu-ND)](2) (6-D), respectively, as a result of dihydrogen activation. These results provide unique insights into the chemistry and electronic structure of late 3d metal nitrides while providing entryway into C-H activation pathways.